From the release:
The war for the Spanish throne has begun; will you join the Grand Alliance or fight for the Sun King using these new units?
When Charles II of Spain died in 1700, he left no heirs. There were two possible contenders for the throne. The Hapsburg, Archuduke CHarles of Austria, and the Bourbon, Philip, Duke of Anjou, who was also the grandson of Louis XIV, the ‘Sun King’. Possesion of the lands and wealth of Spain would make whichever house inherited it immensely powerful on the world stage. And so when Louis XIV recognised his grandson as King Philip V of Spain in 1701, a ‘Grand Alliance’ was created to oppose him, consisting primiarily of the Holy Roman Empire (Austria), The Dutch Republic, Britain, Denmark, Portugal and some factions in Spain along with many of the German states.
The subsequent War of the Spanish Succession was fought in Flanders, in Italy, Spain, along the Rhine and even overseas in the colonies. It involved all of the major European powers either directly or indirectly, as some hired out their armies as mercenaries to the highest bidder.